<?php
/* THE CODE BELOW CONTROLS THE BODY OF THE PAGE. XCR IS A VARIABLE THAT IS USED IN THE NAVIGATION TO PLUG IN THE APPROPRIATE CONTENT INTO THIS SPACE. */
			if ($xcr != "")    { 
			require ("$xcr"); 
			} else { 
			require ("home.php"); 
			} 
			?>

used as "http://www.somesite.com/index.php?xcr=page.php"
page.php is plugged into the template index.php which hold the shell of a site.

php index template include

template

PHP